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Z51.81

Billable

Encounter for therapeutic drug level monitoring

This code does not map to an HCC category in any model (V28, V24, ESRD, RxHCC).

What This Code Means

A visit to check and monitor the level of a therapeutic medication in the patient's blood to ensure it is at the correct dose.

Coding Tips

  • •Commonly used for drugs like warfarin, digoxin, phenytoin, or lithium that require level monitoring
  • •Document the specific drug being monitored for clarity in the medical record

Excludes 1 — Do NOT code together

  • encounter for blood-drug test for administrative or medicolegal reasons (Z02.83)

Code Also

  • any long-term (current) drug therapy (Z79.-)

Code Hierarchy

└Z51Encounter for other aftercare and medical care└Z51.8Encounter for other specified aftercare└Z51.81Encounter for therapeutic drug level monitoring
└Z51.81Encounter for therapeutic drug level monitoring

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